Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
  • H04B7/0868—Hybrid systems, i.e. switching and combining
  • H04B7/0874—Hybrid systems, i.e. switching and combining using subgroups of receive antennas
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
  • H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
  • H04B7/0868—Hybrid systems, i.e. switching and combining
  • H04B7/0871—Hybrid systems, i.e. switching and combining using different reception schemes, at least one of them being a diversity reception scheme
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
  • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity

Definitions

• the invention relates to a method for mobile reception of digital signals, with a plurality of individual receiving antennas, in which a switch is made between individual antenna signals and / or signals formed from linear combinations of antenna signals.
• reception interference occurs which considerably impair reception.
• Such interference is based on the radiation of radio or television waves from more than one direction onto the antenna.
• This so-called multi-path reception occurs because the radio or television waves not only reach the antenna directly from the transmitter, but are reflected, for example, on buildings and also reach the receiving antenna in other ways.
• the reception paths for the several signals picked up by the reception antenna are of different lengths, so that interference interference occurs in the radio or television signal, which results in annoying reception disturbances which considerably impair reception.
• SPARE BLADE 38 14 899 which go back to the same inventor as the present method, furthermore, diversity methods are known in which the phases and / or amplitudes of the high-frequency individual signals are changed by an internal switching clock depending on previously determined phase positions and / or amplitude contributions by one to achieve better reception quality with mobile systems.
• Switchover processes therefore occur in all such mobile reception methods based on the diversity method. These change abruptly the amplitude and / or phase of the received signal, so that interference signals and impulses arise which can assume very high values.
• these interference signals caused by the switching processes lead, for example, to crackling noises, which may adversely affect the reception quality, but are not critical, since these are, for example, opposite other interference are less important in practice compared to tuft disorders.
• the redundancy of the transmission method is sufficient in most cases to identify and eliminate the interference signals caused by the switching processes.
• interference signals or pulses caused by the switching processes are significantly more critical due to the abruptly changing amplitude and / or phase. Due to the transient processes, pulse edges can arise that cannot be distinguished from the edges of the digital pulses. If such an interference pulse occurs at critical points in the digital transmission signal, for example when so-called highly significant bits (MSB-most significant bits) occur or at other particularly relevant points in the digital transmission signal , the transmission of an entire data block can be disturbed.
• MSB-most significant bits An example of mobile digital data transmission is, for example, the so-called radio data system (RDS), which is used for station identification in the FM range. Further data services with digital data transmission are planned. All of these digital transmission methods therefore suffer critically from the said interference signals when diversity methods are used.
• the invention is therefore based on the object of creating a method of the type mentioned at the outset which does not have the disadvantages of conventional methods and in particular enables reliable reception of digital signals with a wide variety of types of diversity systems.
• the object is achieved in that an interference pulse occurring during the switching is orthogonal to the pulses of the data signal.
• the measure according to the invention to place the interference pulse occurring when switching over orthogonal to the data signal, enables averaging in an evaluation circuit. This avoids the fact that the interference pulses occurring due to the switching cause interference in the data bits to be received.
• the orthogonality between the interference pulse and the data signal is formed by the choice of the point in time for the switchover between the individual antenna signals.
• the standing pulse is influenced in such a way that the interference pulse is orthogonal to the pulses of the data signal, that is to say is averaged in the detector filter.
• the interference signal occurs during a less relevant part of the data signal.
• the occurrence of the pulse occurring during the switchover process can be optimally selected with regard to its temporal position, such that the data signal or the useful signal is influenced as little as possible by the switchover signal.
• the digital signals to be transmitted and received have, for example, a certain word form, for example a 16-bit word form. These word forms include low-significant and highly significant bits, also known as LSB (low significant bit) and MSB (most significant bit).
• a suitable choice of the occurrence of the switchover pulse in the region of the insignificant bits ensures that the data signal, if any, is influenced only insignificantly or uncritically, so that the highly significant bits and thus the total useful signal, if any, are only insignificantly affected by the occurrence of switchover signals to be disturbed. This is particularly important if the transmission path in the receiving device, e.g. B. the intermediate frequency filter, no orthogonal to the pulses of the data signal allows pulse shape or this pulse shape can only be generated imperfectly.
• the switchover timing cycle is adapted to the transmission cycle of the data signal.
• This embodiment is particularly advantageous in a diversity system known from DE-Al 37 37 011 if the transmission clock of the data signal is higher than the switchover clock. In this case, synchronization can take place on the block frame.
• the Switching point outside a time window containing decision times. This is particularly advantageous if the transmission clock of the data signal is slower than the changeover clock. In the case of a relatively small transmission clock of the data signal, a certain time window can be left out in such a way that the switchover disturbance is kept away from the decision times, for example.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Radio Transmission System (AREA)
• Mobile Radio Communication Systems (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6402395

Family Applications (1)

Country Status (3)

Cited By (2)

Citations (1)

Family Cites Families (7)

• 1990
  • 1990-03-16 DE DE19904008502 patent/DE4008502A1/de active Granted
  • 1990-12-21 WO PCT/EP1990/002290 patent/WO1991014314A1/de active Application Filing
• 1991
  • 1991-11-13 FI FI915345A patent/FI915345A0/fi not_active Application Discontinuation

Patent Citations (1)

Non-Patent Citations (1)

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